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	<h1>base64 encoding</h1>
	
	<p>base64 is a text encoding method that uses only the ASCII printable characters. The range of characters used is formed by the ranges A-Z, a-z and 0-9 plus the characters "+" and "/". Besides them, the symbol "=" is used as a fill character.<br>
	
	By using 64 characters, these can be represented with 6 bits because 2<sup>6</sup>=64. Base64 works by transforming groups of three bytes (three ASCII characters) into 4 characters codified in base64.<br>
	
	Let's see an example: <br><br>
	<img style="border-width: 0px;" src="resources/base64_EN.png" width="419" height="128" /><br><br>

	
	As we can see, the character "M" has its correponding ASCII value, which in this case it is 77. From the 8 bits needed to represent this value, the first 6 ones are used to establish the correspondence with the fisrt character in base64 format.<br>
	This way the process is carried on until reaching the end of the text. If the number of characters is not a  multiple of threem the fill character "=" is used to complete the sequence. This causes that the length of a base64 encoded text is always a multiple of four.<br><br>
	
	This encoding format is widely spread nowadays because it only uses printable characters. It is used to encode signatures and in some methods of encoding electronic mail.<br>	


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